论文部分内容阅读
目的:研究左氧氟沙星对人血清白蛋白以及在Ca~(2+)存在下左氧氟沙星与人血清白蛋白的结合作用。方法:通过荧光光谱法分析了左氧氟沙星对人血清白蛋白以及Ca~(2+)存在条件下左氧氟沙星对人血清白蛋白荧光淬灭光谱、同步荧光光谱,根据热力学方程讨论两者间主要的作用力类型。结果:在生理条件(pH=7.4,37℃)下,根据Stem-Volmer方程和荧光淬灭双倒数图,确定了左氧氟沙星对人血清白蛋白淬灭类型为静态淬灭,左氧氟沙星对人血清白蛋白的结合常数K=1.46×10~5L·mol~(-1),结合位点n=1.1,根据热力学方法确定作用力类型为疏水作用力;在Ca~(2+)存在条件下,淬灭类型和作用力类型不变,结合常数K=2.38×104L·mol~(-1),结合位点n=1.02。结论:在Ca~(2+)存在条件下,左氧氟沙星对人血清白蛋白的荧光淬灭减弱,结合常数和结合位点均变小。为研究左氧氟沙星的生物学效应,以及左氧氟沙星和Ca~(2+)对蛋白质构象的影响等提供了重要信息。
OBJECTIVE: To study the binding of levofloxacin to human serum albumin and levofloxacin to human serum albumin in the presence of Ca ~ (2+). Methods: The fluorescence quenching spectra and synchronous fluorescence spectra of levofloxacin against human serum albumin (HSA) and human serum albumin (HSA) in the presence of human serum albumin and Ca 2+ were analyzed by fluorescence spectroscopy. The main interaction between the two was discussed based on the thermodynamic equations Types of. Results: According to the Stem-Volmer equation and double-reciprocal plot of fluorescence quenching under physiological conditions (pH = 7.4, 37 ℃), it was confirmed that the quenching type of levofloxacin for human serum albumin was quiescently quenched. Levofloxacin The binding constant K = 1.46 × 10 ~ 5L · mol -1, the binding site n = 1.1, and the type of force was determined to be hydrophobic by thermodynamic method. In the presence of Ca 2+, quenching Type and type of force did not change, the binding constant K = 2.38 × 104L · mol ~ (-1), binding site n = 1.02. CONCLUSION: In the presence of Ca 2+, the fluorescence quenching of human serum albumin by levofloxacin is weakened, and the binding constants and binding sites become smaller. It provides important information for studying the biological effect of levofloxacin and the influence of levofloxacin and Ca 2+ on the protein conformation.